"A fifth of women of child-bearing years have mercury levels in their bodies that we know are not healthy and can cause problems with developing fetuses," said Dr Catherine Thomasson, the executive director of the national lobbying group Physicians for Social Responsibility.

"If you live in a community where there is uncovered dry coal ash deposit and the wind blows you may be inhaling cadmium," PSR's Barbara Gottleib said. "The threats from cadmium are pretty severe: kidney disease, lung diseases like emphysema."

"We already know there’s no safe threshold for lead exposure, and we also know that lead is toxic and a possible carcinogen even at low levels, leading to brain damage and learning disabilities," Kathy Attar, toxics program manager with Physicians for Social Responsibility, a consumer protection group, told IPS.